Stable Flies

Scraping and painting an old barn has never been one of my favorite activities and the presence of stable flies has made that chore even less pleasant.  Unfortunately, these annoying insects seem to have arrived with the horses that we are boarding at our Littleton, Colorado, farm.

While they look very similar to house flies, stable flies (also known as barnyard flies or biting house flies)  do not merely buzz your face or land on your meals.  Since they feed on the blood of mammals and birds, the adults produce a sharp sting when they bite, usually attacking the ankles and lower legs, causing horses to stomp and humans to swat (and perhaps deliver an expletive or two); protection is limited to repellants and clothing coverage.

Females lay their eggs in rotting vegetation, silage, soiled hay or similar farmyard debris.  These hatch into larvae which molt through three stages, pupate and then emerge as adults.  Under warm, summer conditions, this entire process takes about 3-5 weeks, slowing down in the cooler autumn weather and suspended altogether during the winter months (adults live for a few weeks and succumb to the first hard freeze).  Common across much of the globe, stable flies are a scourge for penned livestock and unwelcome visitors for their human handlers; fortunately, they seldom venture indoors and are not known to transmit disease to humans.